A conventional wireless microphone system uses an analog modulation technology (such as frequency modulation, or FM), which does not have a high requirement on the frequency offset between a transmitter and receiver. However, such system is susceptible to interference, and cannot achieve the requirements of high-fidelity sound transmission.
A digital wireless microphone system uses a complete digital modulation, therefore the system is not susceptible to external interference, and the transmission will not lose audio information, which fully realizes high fidelity requirements. However, the digital system has a high requirement on frequency offset for the transceiver. For a stable transmission, the offset requirements is less than 1 parts per million (ppm). However, the frequency offset between the transmitter and receiver is usually greater than 20 ppm. Therefore it is desirable to have a method and device for the receiver to track the frequency of the transmitter, thus achieving the small frequency offset requirement.